This invention relates to power control devices, and, more particularly, to an improved handle assembly therefor.
In conventional power control devices, such as for example, light dimming devices for incandescent lighting systems, power control may be achieved by controlling the conduction time of a switching device, commonly referred to a phase control of power. Power supplied to a lead is controlled through the use of a potentiometer which is a part of a power control circuit connected between the power source and the lighting system. Typical prior art systems have utilized a circular potentiometer having a shaft extending outwardly therefrom to which is attached a knob. By rotating the knob, the resistance of the potentiometer is varied to control the amount of power applied to the lighting system. Typically, the amount of power applied to the lighting system, and correspondingly the amount of light given off thereby, increases as the control knob is turned in a clockwise direction and decreases as the control knob is turned in a counterclockwise direction, a commonly used type of potentiometer having an OFF detented position in which a switch is open when the knob is turned fully in the counterclockwise direction.
While the aforedescribed arrangement where the power control is effected by turning a knob may be suitable for most applications, certain applications and personal subjective preferences may call for an arrangement where the control is achieved in a linear manner, that is by sliding a control handle back and forth. One way of achieving this is to provide a linear potentiometer in place of the aforedescribed circular potentiometer. However, this approach has several disadvantages. For example, a linear potentiometer with a full OFF detented position in which a switch is open is not readily available commercially at a reasonable price. Further, the use of a linear potentiometer in place of a circular potentiometer would require completely different tooling and packaging. This latter factor also would cause a cost increase if both types of controls are to be offered for sale.
It is therefore an object of the present invention to provide a power control device which may be operated in a linear manner.
It is a further object of this invention to provide such a device wherein a readily available conventional circularly operated device may be easily converted to linear operation.